As touch screen smartphones and tablet personal computers (PCs) become common, protection films have been generally used on screen portions (touch screen display portions) of smartphones and tablet PCs.
It is preferable that the protection film is made of a transparent material resistant to a scratch and having excellent static electricity preventing characteristics. The protection film may include, for example, poly ethylene terephthlate (PET), temperature polyurethane (TPU), or the like. In the case in which PET is used as a material of the protection film, low reflection optical PET is used. The low reflection optical PET has light reflectivity lower than that of general PET to secure better visibility of a screen. The protection film may include oriented polypropylene (OPP), polyester, nylon, or the like, in addition to the material described above. Recently, tempered glass is also used as the material of the protection film.
The largest problem in attaching the protection film to the screen portion is introduction of dust. In detail, the dust is introduced onto an adhesion surface or the screen portion due to surface static electricity. In addition, it is not easy to attach the protection film to an accurate position.
Various inventions have been made in order to facilitate the attachment of the protection film, and examples of these inventions are disclosed in Patent Document 1 {Korean Patent Laid-Open Publication No. 10-2014-0147515A (published on Dec. 30, 2014)} and Patent Document 2 {Korean Patent Laid-Open Publication No. 10-2006-0022952A (published on Mar. 13, 2006)}.
However, even in inventions of Patent Document 1 and Patent Document 2, it is difficult to attach the protection film to the accurate position without the introduction of the dust.